Process for obtaining colored discharge effects on dyeings



Patented Jan. 4, 1938 NITED STATES PATENT OFFICE Robert Haller, Riehen, and Charles Graenacher, Basel, Switzerland, assignors to the firm of Society of Chemical Industry in Basle, Basel,

Switzerland No Drawing. Application March 9, 1937, ,Serial No. 120,955. In iswitzerland March 10, 1930 '7 Claims.

It is known that the dyeings produced by means of certain vat dyestuffs can bedischarg'ed by printing them with such oxidizing agents of which the oxidizing effect takes place inan alkaline medium, and by treating the prints with alkalies in the heat. Such dyeings are for example the dyeings produced with indigoid dyestuffs. oxidizing agents of which the effect takes place in .the alkaline medium are for example salts of ferric hydrocyanic acids.

Further, in U. 5. applications 92,244 filed Ju1y 2,3. .19 and N 92,2 5 .nle July 23, l936,"there have been described new ,deriyatives of insoluble to sparingly soluble dyefst'uifs containing at least one hydroxyl group, which are obtained by treating these dyestuffs with acylating agentswhich, in addition to the acylating group, contain atleast one substituent which, if necessary after a, suitable transformation, renders the dyestuff soluble, or increases its solubility. V

' It has now been found that the ester-like, water-soluble products obtainable according to .the above mentioned applications Serial Nos. 92,2451 and 92,245, insofar as they are derived fromwater-insoluble dyestuffs and therefore correspond to the general formula in which R1 represents the radical of awaterinsoluble dyestuff'containingat least one hydroxyl group, and R2 represents an'acyl radical conta in a leas n water- 1gbih ine oup.

. such fasfla fsulfolgroup, a carboxyl group, or a quaternary ammonium group are excellently suited for obtaining colored discharge effects according to the method described above. This .for the reason vbecause theyare stable towards the ,oxidizin'gagents mentioned above, and be- .'c 'use the dyestuffs may be regenerated from these products .by agents having an' alkaline effect. The process ,rnaybe carried outin such amanner that the ,namedproducts are printed, for example with potassium ferricyanide or potassium chlorate onto the goods dyed with vat dyestuffs capable of being discharged with potassium ferricyanide or with another oxidizing agent having a like effect, and that after drying and if necessary after steaming the goods are passed through alkalies. Discharge of the vat dyestuff capable of discharge, formation of dyestuff by splitting of the printed acylating radical R2, and formation of the insoluble dyestuff of the general formula Rr-OH taking place thereby. This method of working makes it possible to ser .No-

combine colored and white discharge effects. The new process has the further advantage that the undischarged places are not blurred by preparations, as is for example the case if alkaline oxidizing discharges are printed onto goods which have been dyed with vat dyestuffs and naphtholized.

then The following examples illustrate the invention:--

Example 1 Cotton is dyed a medium blue with Ciba Blue 23 (Colour Index No. i184). The material thus dyed is then printed with the following two I 2. Red discharge- 10p grams of the condensationflproduct from diazotized 2;5-di chlo,roaniline and the forthoanisidide of the 2 B-hydroxynaphthoic acid with 2 moles of'sulfobenzoic acid chloride.

Grams Water .Neutral starch ,traga ca,nth thickening Potassium ferricyanide Zinc oxide Theprinted material is passed through a printing pastesz- 1. White discharge.

Grams Potassium ferricyanide 150 Neutr'al' starch tragacanth thickening 600 Water 250 bath of C. containing caustic soda solution of 13 B., and 10 cc. of bisulfite, and after ab minute the goods are washed, acidified,

out 1 and.

soaped. There are obtained whiteand scarletred effects on a blue ground.

2. Red discharge. grams of the condensation product of the azo-dyestufi from diazotized meta-chloroaniline and the anilide of the 2:3- hydroxynaphthoic acid with 2 moles of sulfobenzoic' acid chloride.

Grams Phiodiglycol (HOC2H4S-C2H4OH) Water Starch tragacanth thickening 400 Potassium ferricyanide 100 Zinc oxide 100 The printed material is treated with a caustic soda solution, washed, acidified and soaped, as described in Example 1. There are obtained orange and white effects on a blue ground.

The process is similar with the other products described in applications Serial Nos. 92,244 and 92,245. Thus, for example with the condensa tion product of the azo-dyestuff from tetrazotized 2-methyl-4:4-diamino 4 5 methoxy-azobenzene and Z-hydroxynaphthalene and subsequent esterification with 4-chloromethyl benzoylchloride in pyridine solution there are obtained brown effects on a blue ground.

Colored effects can also be obtainedwith dyestuffs which do not belong to the azo-series. Violet discharge effects are for example obtained with aid of the product obtained by the action of the 3:5-benzoic acid disulfochloride on 1:5-dibenzoyldiamino-4 8-dihydroxyanthraquinone.

Similar effects are obtained if instead of Ciba Blue 213 indigo or monochlorindigo or monobromindigo are used.

What we claim is:-

1. Process for obtaining colored discharge effects on vat dyeings capable of being discharged by means of oxidizing agents of which the oxidizing effect takes place in an alkaline medium, by printing these dyeings with such oxidizing agents and developing them with alkalies, comprising applying a discharge paste containing an alkaline oxidizing agent and an ester-like, water soluble product of the general formula R1OR2 in which R1 represents the radical of a waterinsoluble dyestufi containing at least one hydroxyl group, and R2 represents an acyl radical containing at least one water-solubilizing group.

2. Process for obtaining colored discharge effects on vat dyeings capable of being discharged by means of oxidizing agents of which the oxidizing effect takes place in an alkaline medium, by printing these dyeings with such oxidizing agents and developing them with alkalies, comprising applying a discharge paste containing an alkaline oxidizing agent and an ester-like, watersoluble product of the general formula R1-OR2 in which R1 represents the radical of a waterby printing these dyeings with such oxidizing agents and developing them with alkalies, comprising applying a discharge paste containing an alkaline oxidizing agent and an ester-like, Watersoluble product of the general formula in which R1 represents the radical of a waterinsoluble azo-dyestuff containing at least one hydroxyl group, and R2 represents an acyl radical containing at least one sulfo group.

4. Process for obtaining colored discharge effects on vatdyeings capable of being discharged by means of potassium ferricyanide by printing these dyeings with potassium ferricyanide and developing them with alkalies, comprising applying a discharge paste containing potassium ferricyanide and an ester-like, water-soluble product of the general formula in which R1 represents the radical of a Waterinsoluble azo-dyestuff containing at least one hydroxyl group, and R2 represents an acyl radical containing at least one sulfo group.

5. Discharge pastes comprising alkaline oxidizing agents which are used for discharging goods dyed with vat dyestuffs, and. an ester-like,

'water-soluble product of the formula in which R1 represents the radical of a waterinsoluble dyestuff containing at least one hydroXyl group, and R2 represents an acyl radical containing at least one water-solubilizing group.

6. Discharge pastes comprising alkaline oxidizing agents which are used for discharging goods dyed with vat dyestuffs, and an ester-like, water-soluble product of the general formula in which R1 represents the radical of a waterinsoluble azo-dyestuff containing at least one hydroxyl group, and R2 represents an acyl radical containing at least one sulfo group.

7. Discharge pastes comprising potassium ferricyanide and an ester-like, water-soluble product of the general formula R1VO'VR2 in which R1 represents the radical of a waterinsoluble azo-dyestuff containing at least one hydroxyl group, and R2 represents an acyl radical containing at least one sulfo group.

ROBERT HALLER. CHARLES GRAENACHER. 

